1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
/*****************************************************************
Implementation of the fractional Brownian motion algorithm. These
functions were originally the work of F. Kenton Musgrave.
For documentation of the different functions please refer to the
book:
"Texturing and modeling: a procedural approach"
by David S. Ebert et. al.
******************************************************************/
#if defined (_MSC_VER)
#include <qglobal.h>
#endif
#include <time.h>
#include <stdlib.h>
#include "fbm.h"
#if defined(Q_CC_MSVC)
#pragma warning(disable:4244)
#endif
/* Definitions used by the noise2() functions */
#define B 0x100
#define BM 0xff
#define N 0x1000
#define NP 12 /* 2^N */
#define NM 0xfff
static int p[B + B + 2];
static float g3[B + B + 2][3];
static float g2[B + B + 2][2];
static float g1[B + B + 2];
static int start = 1;
static void init(void);
#define s_curve(t) ( t * t * (3. - 2. * t) )
#define lerp(t, a, b) ( a + t * (b - a) )
#define setup(i,b0,b1,r0,r1)\
t = vec[i] + N;\
b0 = ((int)t) & BM;\
b1 = (b0+1) & BM;\
r0 = t - (int)t;\
r1 = r0 - 1.;
#define at3(rx,ry,rz) ( rx * q[0] + ry * q[1] + rz * q[2] )
static float noise3(float vec[3]);
/* Fractional Brownian Motion function */
double fBm( Vector point, double H, double lacunarity, double octaves,
int init )
{
double value, frequency, remainder;
int i;
static double exponent_array[10];
float vec[3];
/* precompute and store spectral weights */
if ( init ) {
start = 1;
srand( time(0) );
/* seize required memory for exponent_array */
frequency = 1.0;
for (i=0; i<=octaves; i++) {
/* compute weight for each frequency */
exponent_array[i] = pow( frequency, -H );
frequency *= lacunarity;
}
}
value = 0.0; /* initialize vars to proper values */
frequency = 1.0;
vec[0]=point.x;
vec[1]=point.y;
vec[2]=point.z;
/* inner loop of spectral construction */
for (i=0; i<octaves; i++) {
/* value += noise3( vec ) * exponent_array[i];*/
value += noise3( vec ) * exponent_array[i];
vec[0] *= lacunarity;
vec[1] *= lacunarity;
vec[2] *= lacunarity;
} /* for */
remainder = octaves - (int)octaves;
if ( remainder ) /* add in ``octaves'' remainder */
/* ``i'' and spatial freq. are preset in loop above */
value += remainder * noise3( vec ) * exponent_array[i];
return( value );
} /* fBm() */
float noise3(float vec[3])
{
int bx0, bx1, by0, by1, bz0, bz1, b00, b10, b01, b11;
float rx0, rx1, ry0, ry1, rz0, rz1, *q, sy, sz, a, b, c, d, t, u, v;
int i, j;
if (start) {
start = 0;
init();
}
setup(0, bx0,bx1, rx0,rx1);
setup(1, by0,by1, ry0,ry1);
setup(2, bz0,bz1, rz0,rz1);
i = p[ bx0 ];
j = p[ bx1 ];
b00 = p[ i + by0 ];
b10 = p[ j + by0 ];
b01 = p[ i + by1 ];
b11 = p[ j + by1 ];
t = s_curve(rx0);
sy = s_curve(ry0);
sz = s_curve(rz0);
q = g3[ b00 + bz0 ] ; u = at3(rx0,ry0,rz0);
q = g3[ b10 + bz0 ] ; v = at3(rx1,ry0,rz0);
a = lerp(t, u, v);
q = g3[ b01 + bz0 ] ; u = at3(rx0,ry1,rz0);
q = g3[ b11 + bz0 ] ; v = at3(rx1,ry1,rz0);
b = lerp(t, u, v);
c = lerp(sy, a, b);
q = g3[ b00 + bz1 ] ; u = at3(rx0,ry0,rz1);
q = g3[ b10 + bz1 ] ; v = at3(rx1,ry0,rz1);
a = lerp(t, u, v);
q = g3[ b01 + bz1 ] ; u = at3(rx0,ry1,rz1);
q = g3[ b11 + bz1 ] ; v = at3(rx1,ry1,rz1);
b = lerp(t, u, v);
d = lerp(sy, a, b);
return lerp(sz, c, d);
}
static void normalize2(float v[2])
{
float s;
s = sqrt(v[0] * v[0] + v[1] * v[1]);
v[0] = v[0] / s;
v[1] = v[1] / s;
}
static void normalize3(float v[3])
{
float s;
s = sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
v[0] = v[0] / s;
v[1] = v[1] / s;
v[2] = v[2] / s;
}
static void init(void)
{
int i, j, k;
for (i = 0 ; i < B ; i++) {
p[i] = i;
g1[i] = (float)((rand() % (B + B)) - B) / B;
for (j = 0 ; j < 2 ; j++)
g2[i][j] = (float)((rand() % (B + B)) - B) / B;
normalize2(g2[i]);
for (j = 0 ; j < 3 ; j++)
g3[i][j] = (float)((rand() % (B + B)) - B) / B;
normalize3(g3[i]);
}
while (--i) {
k = p[i];
p[i] = p[j = rand() % B];
p[j] = k;
}
for (i = 0 ; i < B + 2 ; i++) {
p[B + i] = p[i];
g1[B + i] = g1[i];
for (j = 0 ; j < 2 ; j++)
g2[B + i][j] = g2[i][j];
for (j = 0 ; j < 3 ; j++)
g3[B + i][j] = g3[i][j];
}
}
|
